For a recording device such as a facsimile machine, for example, a thermal printer comprising a thermal head and a platen roller may be used. Thermal heads mounted on such a thermal printer comprise a substrate, a plurality of heat-generating portions arranged on the substrate, an electrode pattern for supplying power to the heat-generating portions, and a protective layer covering the heat-generating portions and the electrode pattern. Such a thermal printer can make a print by sliding and pressing a recording medium against the protective layer located on the heat-generating portions with the platen roller.
Such thermal heads comprise one or more steps on the surface of the protective layer. The steps are made by projecting the electrode pattern from the substrate. When the recording medium is slid and pressed against the protective layer having a step on the surface in such a manner, variations in the frictional force between the protective layer and the recording medium may be caused, resulting in wrinkling of the recording medium.
At the same time, when irregularities on the protective layer are smoothed to address problems due to wrinkling as described above, the overall thickness of the layer formed on the heat-generating portions will be thickened. A thermal head with such a configuration may require more time to transfer the heat generated by the heat-generating portions to the recording medium. Therefore, there is a need for recording heads that provide an improved image.